Brother DB2-B791 & B7910 Parts Book [section 1]

Of course, the parts book comes in second to the manual. Or at least the two together form a force to be reckoned with like no other. Look at the parts individually, look how they go together, create a super-structure. Once you have made it through the introduction and the tables of contents, the way to view these is with the diagram pages accompanied by their numerical lists, to identify the parts names.

Partsbk page#1Partsbk page#2Partsbk page#3Partsbk page#4Partsbk page#5Partsbk page#6 Partsbk page#7Partsbk page#8Partsbk page#9Partsbk page#10Partsbk page#11Partsbk page#12Partsbk page#13Partsbk page#14Partsbk page#15Partsbk page#16Partsbk page#17Partsbk page#18Partsbk page#19Partsbk page#20Partsbk page#21Partsbk page#22Partsbk page#23Partsbk page#24Partsbk page#25

* Due to the parts book’s length, this will be posted in three sections.

** This book is available in hard-copy form, from Dunlap Sunbrand International, which there is a link to in the side bar of this site.

On Thread – A Complicated Dilemma [part one of more to come]

[“A fine cord of a fibrous material, such as cotton or flax, made of two or more filaments twisted together and used in sewing, needlework and the weaving of cloth.” – taken from Infomat]

Thread, thread – thread. This has been a long pressing issue with the sewing world, possibly one of the oldest and most important one at that. It’s hard to imagine what garments, or other textile products would be like, if the quality of thread was considered irrelevant, or even if, in choosing quality thread it was an irrelevant action beyond, say, the color choice. Obviously by now this is not the case, with many companies devoted to the future of thread and it’s ability to mend our existence, solve unusual problems, and uphold complex structures (?) – an immense variety of thread is being produced every day. American&Efird, ApparelSearch, Gütermann, H.P. Thread, The Thread Exchange, Coats&Clark to name a few, gets things going: and so on and so forth we begin to see how important our threading obligations are. After writing about the silk thread used on those mysterious black denim jeans, things started to unravel a bit, and it seemed time to confront this topic, if not to settle it, to at least begin the investigation.

However there are a few ground rules here that should be acknowledged – but do not need to be adhered to in the long run by any means. Between the lineage of sewing machines which have led up to now, from the old Singer Stylist 534 to the Brother DB2-B791-015, there have been some consistencies and inconsistencies with threading. The inconsistencies are simple, every time a thread has been chosen and used, it has always been a domesticated thread available from your average sewing machine (or fabric) dealer. Of course this in itself is consistent, but based on not sourcing out “industrial” thread for these “industrial” machines, the argument is that only one side of the threading spectrum has been administered, leaving an inconsistent, or at least narrow look at what threads are the best.

The reasons for straying away from “industrial” thread choices (figure “industrial” thread here to be anything you can purchase in a .5 – 1 pound cone or more) are varied and complicated. A lot of the discouragement was due to availability of the information behind the thread choices. In the L.A. Fashion District, it was possible to buy millions of feet if not more in thread length, but if you were buying in bulk, the choices of what those many feet would consist of were limited, you could find either lightweight polyester thread, or some nylon based serger/overlock threads. When you wanted to find something that was blended with either cotton, polyester, nylon, etc. it was impossible, as the bulk threads are packaged for economic reasons not informational reasons, therefore the “nutrition” labels are not there which may display the percentage of the blends (all of the thread was/is either 100% polyester, or 100% nylon, the rest a mystery). Of course, most of these threads will get most of the jobs done – however around the Brother DB2-B791-015 – these matters are not left to chance, why have a great sewing machine and great fabric and skimp out on the most important detail? These experiences left one essential question, where does big industry get bulk thread from, and why, and what tasks is it used for if at all? Looking back on it, many of the small spools of domesticated thread seem to be of much higher quality than what was available on the shelves in huge amounts, it may be a matter of customization vs. streamlining production, but then what threads do our smaller manufacturers use? As an example, Work Custom Jeans of L.A. always had pegs and pegs of the tiny little Gütermann “Heavy Duty” thread in 30 meter spools, this is in no way economical – but it does ensure a magnificent product. It would certainly benefit Work to trade those little bundles in for cones – saving time and money. Does Gütermann offer this option, and if so, is it only to the dominant powerhouse factories where all different major label clothing and accessory companies are probably having their products made under one roof? More than likely this deficit of thread is caused by domestic demands, who needs 1000 plus yards of expensive thread anyway?

The consistencies lay in that most of the domesticated threads purchased, have been used over and over, seeing their faults and their merits. The readily available threads have one huge advantage to their name – they are well labeled. The options go on and on, and if you purchase one that does not work out, you aren’t left with a ton to waste. A telling tale; with some looking around – the thread issue really came to light when making a pair of jeans. While using a 100% nylon thread, a flood of questions came to the forefront. The nylon was strong, but it was not quite the right weight, plus it would melt under the pressure/heat of the iron, when you were not paying close enough attention. So, a generic 100% polyester thread was tested, this time it was even finer in weight so the look simply wasn’t there, also it was not as strong, but at least it withstood heat better. Unfortunately cotton thread was too light in terms of it’s diameter (coarse-ness or gauge). What would have been great was a blended thread, part nylon, part polyester, and maybe even part cotton. Thus the search began, and after reading the “nutrition” labels of almost every single spool of thread at the shop, it was evident that threads were going to shape things quite a bit. While Coats&Clark offers a lot of blended threads, Gütermann typically produces better single-fiber threads. However, a lot of what determines a threads strength depends on how it was wound, and how consistent each individual fiber was to begin with, whether it had a smooth and even surface, how uniform it was in shape, etc. Some nylon threads have been very good at withstanding heat, and some not so much, so even with the same material your results are going to differ quite a bit.

Here are some thoughts, and propositions on where then to go when choosing a thread. For all intents and purposes, suppose that there is no limit to whats available, and anything and everything is at a reasonable price, in whatever quantity needed. First – strength, if strength is what your after, then you may want to lean towards a natural fiber like cotton, or wool, but in order to provide that strength, these choices would have to be unreasonably thick in their diameter (coarse-ness or gauge). Moving to polyester leaves us with an even stronger fiber that can achieve the same strength with less thickness. Nylon accomplishes this even better as it has the highest strength to weight ratio – although it is most susceptible to heat. Second – heat, when it comes to heat first consider that your encounters with it will be in two places – one is from contact with an iron – and two is from friction during the stitching process. More than likely the iron is going to have a higher temp, but at least it is a less common application, where as friction under the stitching process is going to be a factor every time we build a sewn item. This friction could come from just about anywhere, but will mainly reside in the eye of the needle as the thread passes through, and against the back of the hole in your needle-plate, or on your feed dog as is the case with the Brother DB2-B791-015 and any other compound needle feed machine (and walking foot too). Any other friction occurring above the needle will probably not get hot enough to matter, and if your sewing through a very thick item (as the case may be for sail makers) friction and heat will surely occur within the actual punctured holes of the material, this could cause melting of both thread and material. If and when this heating does occur, it will cause the thread materials outer fibers to rub off more easily and cause some (amount of) clogging in the tight areas. If this factor increases exponentially it may cause the thread to break because of how much material loss has occurred, that coupled with the tremendous amount of tension that thread endures will certainly open up the possibility of breakage. So if fighting heat is an issue, consider that nylon thread will probably be the most finicky in these situations, with polyester being in the middle, and then finally cotton and other natural fibers being the most resistant to high temperature applications. Third – how does the stiffness of the thread affect stitching? In some applications certain thread will not embed itself in the materials very easily – if at all. This is a big deal, because uniform stitching, pulling evenly from both sides is going to ensure a strong seam, a protected seam (as there will be fewer loose loops waiting for something to snag on) which will promote a longer life cycle, and a better looking seam in terms of aesthetics. With stiffness, we also have to figure how much of that comes from the diameter of the thread and conversely how that effects the seam strength/quality/construction. Think of a length of yarn, that would be an example of a thread that is very soft and supple, but has a very large diameter vs. a length of fishing line which has a very small diameter but is relatively stiff considering it’s size – this would display that large diameters do not necessarily have to be extremely stiff, and thin mono-filaments are not always going to be flimsy. Now using something more common as an example: the Gütermann 100% silk thread that was used for the black denim jeans was very supple, and almost elastic in nature, and has a rather large diameter – Coats&Clark makes a “button & carpet” thread which is probably equal in diameter to the silk thread, but is far stiffer and does not stretch at all (within human parameters at least). Here are two threads which sew very differently yet have the same outer dimensions (nearly), the “Button & carpet” thread requires a very high tension setting to get it to nest in the fabric, while the silk thread requires very little adjustment of the/a/your machine to achieve the proper stitch depth. Or, the Coats&Clark “extra strong” quilting thread vs. Gütermann’s “heavy duty” upholstery thread (large spool): the Coats&Clark is a much finer thread in diameter than the Gütermann, but it is also a lot stiffer – yet not quite as strong. The Coats&Clark has a bit more trouble passing through the needle and making all of those turns, whereas the Gütermann can complete the route much more easily and embed itself in your desired materials with ease, however – with patience, you can set up the quilting thread to work just fine and achieve a more hidden seam. These are all very subjective reasonings, hopefully it will help illuminate some of the discourse that is the deciding factor of how a garment or other textile product maintains an elevated level of integrity.

Hmmm, with this in mind – maybe some of the theory can be approached. With all these overriding factors flying around, what then is the ultimate thread?